Systems and methods of performing power control of a physical channel in a communication system

ABSTRACT

Systems and methods for performing power control of a physical channel in a communication system are provided. In one exemplary embodiment, a method in a wireless device of performing power control of a physical channel in a wireless communication system may include determining a transmission power for a transmission on the physical channel according to a power control loop. Further, the loop may specify the transmission power based on at least one parameter. Also, a value of the at least one parameter may be dependent on which of different transmission time interval (TTI) lengths defined as usable on the physical channel is selected for the transmission on the physical channel.

TECHNICAL FIELD

The present disclosure relates generally to the field of communications,and in particular to performing power control of a physical channel in acommunication system.

BACKGROUND

Packet data latency is one of the performance metrics that vendors,operators and end-users (e.g., via speed test applications) regularlymeasure. Latency measurements are performed in all phases of thelifetime of a radio access network system such as when verifying a newsoftware release or system component, when deploying a system and whenthe system is in commercial operation.

One performance metric that guided the design of Long Term Evolution(LTE) was to provide shorter latencies than previous generations of 3GPPradio access technologies (RATs). By doing so, LTE is recognized by endusers as providing faster access to the Internet and shorter datalatencies than these previous generations. Packet data latency isimportant not only for the perceived responsiveness of the system butalso indirectly influences the throughput of the system. HTTP/TCP is thedominating application and transport layer protocol used on theInternet. According to HTTP Archive (http://httparchive.org/trends.php),the typical size of HTTP based transactions over the Internet range fromtens of kilobytes to one megabyte. In this range, the TCP slow startperiod is a significant part of the total transport period of the packetstream. During TCP slow start, the performance is limited by latency.Hence, the average throughput can be improved by reducing the latencyfor this type of TCP based data transactions.

Furthermore, radio resource efficiency can be improved by reducinglatency. For instance, lower packet data latency could increase thenumber of transmissions that are possible within a certain delay bound.Hence, higher Block Error Rate (BLER) targets could be used for datatransmissions, resulting in freeing up radio resources to improve thecapacity of the system.

Another area to reduce packet latency is to reduce the transport time ofdata and the associated control signaling. For instance, in LTE Release8, a transmission time interval (TTI) corresponds to one subframe oflength (i.e., 1 millisecond). One such TTI is constructed using fourteenorthogonal frequency division multiplexing (OFDM) or single-carrier,frequency-division multiple access (SC-FDMA) symbols in the case ofnormal cyclic prefix (CP) and twelve OFDM or SC-FDMA symbols in the caseof extended CP. For LTE Release 13, shorter TTIs (i.e., shorter than theLTE release 8 TTI) are being investigated. These shorter TTIs may be anyduration in time and may include resources on a number of OFDM orSC-FDMA symbols that are within the LTE Release 8 TTI (i.e., 1millisecond). For instance, the duration of a short TTI may be 0.5milliseconds (i.e., 7 OFDM or SC-FDMA symbols for normal CP) or may be 2symbols. Accordingly, there is a need for improved techniques to performpower control of a physical channel in a communication system such asfor a transmission on a physical channel having a short TTI. Inaddition, other desirable features and characteristics of the presentdisclosure will become apparent from the subsequent detailed descriptionand embodiments, taken in conjunction with the accompanying figures andthe foregoing technical field and background.

The Background section of this document is provided to place embodimentsof the present disclosure in technological and operational context, toassist those of skill in the art in understanding their scope andutility. Unless explicitly identified as such, no statement herein isadmitted to be prior art merely by its inclusion in the Backgroundsection.

SUMMARY

The following presents a simplified summary of the disclosure in orderto provide a basic understanding to those of skill in the art. Thissummary is not an extensive overview of the disclosure and is notintended to identify key/critical elements of embodiments of thedisclosure or to delineate the scope of the disclosure. The sole purposeof this summary is to present some concepts disclosed herein in asimplified form as a prelude to the more detailed description that ispresented later.

Briefly described, embodiments of the present disclosure relate toperforming power control of a physical channel in a communicationsystem. According to one aspect, a method in a wireless device ofperforming power control of a physical channel in a wirelesscommunication system may include determining a transmission power for atransmission on the physical channel according to a power control loop,wherein the loop specifies the transmission power based on at least oneparameter. Further, a value of the at least one parameter may bedependent on which of different transmission time interval (TTI) lengthsdefined as usable on the physical channel is selected for thetransmission on the physical channel.

According to another aspect, each TTI length usable on the physicalchannel may be based on a different value for the at least oneparameter.

According to another aspect, the value of the at least one parameter mayfurther depend on which of different transmission formats defined asusable on the physical channel is selected for the transmission on thephysical channel.

According to another aspect, each transmission format usable on thephysical channel may be based on a different value for the at least oneparameter.

According to another aspect, the at least one parameter has a differentvalue for each TTI length usable on the physical channel.

According to another aspect, the at least one parameter has a differentvalue for each transmission format usable on the physical channel.

According to another aspect, the value of the at least one parameter maybe based on a power adjustment for the transmission on the physicalchannel having the selected TTI length.

According to another aspect, the value of the at least one parameter maybe based on a ratio of a power adjustment for the transmission on thephysical channel having the selected TTI length and a power adjustmentfor the transmission on the physical channel having a predetermined TTIlength.

According to another aspect, the value of the at least one parameter maybe based on a number of symbols in the transmission on the physicalchannel having the selected TTI length.

According to another aspect, the value of the at least one parameter maybe based on a ratio of a number of symbols in a transmission on thephysical channel having the selected TTI length and a number of symbolsin a transmission on the physical channel having a predetermined TTIlength.

According to another aspect, the ratio may be represented as follows:

${10{\log_{10}\left( \frac{{TTIsymbols}_{selected}}{{TTIsymbols}_{predetermined}} \right)}},$

wherein TTIsymbols_(selected) is the selected number of TTI symbols, andTTIsymbols_(predetermined) is the predetermined number of TTI symbols.

According to another aspect, the ratio is further represented asfollows:

${a\; 10{\log_{10}\left( \frac{{TTIpilotsymbols}_{selected}}{{TTIpilotsymbols}_{predetermined}} \right)}} + {b\; 10{\log_{10}\left( \frac{{TTIcontrolsymbols}_{selected}}{{TTIcontrolsymbols}_{predetermined}} \right)}}$

wherein the selected number of TTI symbols corresponds to a selectednumber of pilot symbols (TTIpilotsymbols_(selected)) and a selectednumber of control symbols (TTIcontrolsymbols_(selected)), and thepredetermined number of TTI symbols corresponds to a predeterminednumber of pilot symbols (TTIpilotsymbols_(predetermined)) and apredetermined number of control symbols(TTIcontrolsymbols_(predetermined)).

According to another aspect, the predetermined number of pilot symbolsis six (6) and the predetermined number of control symbols is eight (8).

According to another aspect, the predetermined number of TTI symbols isfourteen (14).

According to another aspect, the value of the at least one parameter isbased on a ratio of the selected TTI length and a predetermined TTIlength.

According to another aspect, the ratio is represented as follows:

${10{\log_{10}\left( \frac{{TTIlength}_{selected}}{{TTIlength}_{predetermined}} \right)}},$

wherein TTIlength_(selected) is the selected TTI length, andTTIlength_(predetermined) is the predetermined TTI length.

According to another aspect, the ratio is further represented asfollows:

${{a\; 10{\log_{10}\left( \frac{{TTIpilotlength}_{selected}}{{TTIpilotlength}_{predetermined}} \right)}} + {b\; 10{\log_{10}\left( \frac{{TTIcontrollength}_{selected}}{{TTIcontrollength}_{predetermined}} \right)}}},$

wherein the selected TTI length corresponds to a selected pilot symbolslength (TTIpilotlength_(selected)) and a selected control symbols length(TTIcontrollength_(selected)). Further, the predetermined TTI lengthcorresponds to a predetermined pilot symbols length(TTIpilotlength_(predetermined)) and a predetermined control symbolslength (TTIcontrollength_(predetermined)). Also, a and bare constants.

According to another aspect, the predetermined TTI length is onemillisecond.

According to another aspect, the value of the at least one parameter isbased on a predetermined received power for the physical channel havingthe selected TTI length.

According to another aspect, the value of the at least one parameter isbased on an adjustment that depends on whether frequency hopping is usedfor the transmission on the physical layer having the selected TTIlength.

According to another aspect, the physical channel is a control channel.

According to another aspect, the physical channel is an uplink channel.

According to another aspect, a wireless device for performing powercontrol of physical channels in a wireless communication system may beconfigured to determine a transmission power for a transmission on thephysical channel according to a power control loop. The loop may specifythe transmission power based on at least one parameter. Further, a valueof the at least one parameter may be dependent on which of different TTIlengths defined as usable on the physical channel is selected for thetransmission on the physical channel.

According to another aspect, a wireless device for performing powercontrol of physical channels in a wireless communication system mayinclude a processor and a memory. Further, the memory containsinstructions executable by the processor whereby the wireless device maybe configured to determine a transmission power for a transmission onthe physical channel according to a power control loop. The loop mayspecify the transmission power based on at least one parameter. Also, avalue of the at least one parameter being dependent on which ofdifferent TTI lengths defined as usable on the physical channel isselected for the transmission on the physical channel.

According to another aspect, a wireless device for performing powercontrol of physical channels in a wireless communication system,comprises a processor and a memory. The memory containing instructionsexecutable by the processor whereby the wireless device is configured todetermine a transmission power for a transmission on the physicalchannel according to a power control loop, wherein the loop specifiesthe transmission power based on at least one parameter, with a value ofthe at least one parameter being dependent on which of differenttransmission time interval (TTI) lengths defined as usable on thephysical channel is selected for the transmission on the physicalchannel.

According to another aspect, the value of the at least one parameterfurther depends on which of different transmission formats defined asusable on the physical channel is selected for the transmission on thephysical channel.

According to another aspect, the value of the at least one parameter isbased on a number of symbols in the transmission on the physical channelhaving the selected TTI length.

According to another aspect, a method in a wireless device forperforming power control of physical channels in a wirelesscommunication system, comprises receiving, by the wireless device, froma network node an indication of a value of at least one parameter whichis dependent on which of different transmission time interval (TTI)lengths defined as usable on the physical channel is selected for thetransmission on the physical channel. A transmission power for atransmission on the physical channel is according to a power controlloop, and wherein the power control loop specifies the transmissionpower based on the parameter.

According to another aspect, a method in a network node for performingpower control of physical channels in a wireless communication system,comprising: transmitting, by the network node, to a wireless device anindication of a value of at least one parameter which is dependent onwhich of different transmission time interval (TTI) lengths defined asusable on the physical channel is selected for the transmission on thephysical channel. A transmission power for a transmission by thewireless device on the physical channel is according to a power controlloop, and wherein the power control loop specifies the transmissionpower based on the parameter.

According to another aspect, a network node for performing power controlof physical channels in a wireless communication system, the networknode configured to:

transmit, to a wireless device, an indication of a value of at least oneparameter which is dependent on which of different transmission timeinterval (TTI) lengths defined as usable on the physical channel isselected for the transmission on the physical channel. A transmissionpower for a transmission by the wireless device on the physical channelis according to a power control loop, and wherein the power control loopspecifies the transmission power based on the parameter.

According to another aspect, a network node for performing power controlof physical channels in a wireless communication system comprises aprocessor and a memory, the memory containing instructions executable bythe processor whereby the network node is configured to transmit, to awireless device, a value of at least one parameter which is dependent onwhich of different transmission time interval (TTI) lengths defined asusable on the physical channel is selected for the transmission on thephysical channel, wherein a transmission power for a transmission by thewireless device on the physical channel is according to a power controlloop, and wherein the power control loop specifies the transmissionpower based on the parameter.

According to another aspect, a computer program product may be stored ina non-transitory computer readable medium for controlling a wirelessdevice in a communication system. Further, the computer program productincludes software instructions which, when run on the wireless device,may cause the wireless device to determine a transmission power for atransmission on the physical channel according to a power control loop.The loop may specify the transmission power based on at least oneparameter. Also, a value of the at least one parameter may be dependenton which of different TTI lengths defined as usable on the physicalchannel is selected for the transmission on the physical channel. Inaddition, a carrier may contain the computer program. The carrier may beone of an electronic signal, optical signal, radio signal, or computerreadable storage medium.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will now be described more fully hereinafter withreference to the accompanying drawings, in which embodiments of thedisclosure are shown. However, this disclosure should not be construedas limited to the embodiments set forth herein. Rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the disclosure to thoseskilled in the art. Like numbers refer to like elements throughout.

FIG. 1 illustrates one embodiment of a system for performing powercontrol of a physical channel in accordance with various aspects asdescribed herein.

FIG. 2 illustrates one embodiment of a wireless device for performingpower control of a physical channel in accordance with various aspectsas described herein.

FIG. 3 illustrates another embodiment of a wireless device forperforming power control of a physical channel in accordance withvarious aspects as described herein.

FIG. 4 illustrates another embodiment of a wireless device forperforming power control of a physical channel in accordance withvarious aspects as described herein.

FIG. 5 illustrates one embodiment of method for performing power controlof a physical channel in accordance with various aspects as describedherein.

FIG. 6 illustrates another embodiment of a wireless device forperforming power control of a physical channel in accordance withvarious aspects as described herein.

FIG. 7 illustrates another embodiment of method by a wireless device forperforming power control of a physical channel in accordance withvarious aspects as described herein.

FIG. 8 illustrates one embodiment of a network node for performing powercontrol of a physical channel in accordance with various aspects asdescribed herein.

FIG. 9 illustrates another embodiment of a network node for performingpower control of a physical channel in accordance with various aspectsas described herein.

FIG. 10 illustrates another embodiment of a network node for performingpower control of a physical channel in accordance with various aspectsas described herein.

FIG. 11 illustrates one embodiment of method by a network node forperforming power control of a physical channel in accordance withvarious aspects as described herein.

FIG. 12 illustrates an example where uplink sTTIs are scheduled andclosed loop power control (f_(c)(i)) is updated before the onemillisecond uplink transmission is performed.

FIG. 13 illustrates a 20 usec. transient period between messages forsTTI.

DETAILED DESCRIPTION

For simplicity and illustrative purposes, the present disclosure isdescribed by referring mainly to an exemplary embodiment thereof. In thefollowing description, numerous specific details are set forth in orderto provide a thorough understanding of the present disclosure. However,it will be readily apparent to one of ordinary skill in the art that thepresent disclosure may be practiced without limitation to these specificdetails. In this description, well known methods and structures have notbeen described in detail so as not to unnecessarily obscure the presentdisclosure.

This disclosure includes describing systems and methods for performingpower control of a physical channel in a communication system. Forexample, FIG. 1 illustrates one embodiment of a system 100 forperforming power control of a physical channel in accordance withvarious aspects as described herein. In FIG. 1, the system 100 mayinclude a network node 101 with coverage area 103, and a wireless device105. Each of the network node 101 and the wireless device 105 may senddifferent signals to the other. In one example, the network node 101 maytransmit the signal 107 to the wireless device 105. In another example,the wireless device 105 may transmit the signal 107 to the network node101. The signal 107 may include a series of transmissions 123 a-d on aphysical channel 121. Further, these transmissions may have a certaintransmission time interval (TTI) length 125. The wireless device 105 maydetermine a transmission power for each transmission on the physicalchannel 121 having the certain TTI length 125 according to a powercontrol loop. The power control loop may specify the transmission powerbased on at least one parameter 111. Further, a value of the at leastone parameter 111 may be dependent on which of different TTI lengthsdefined as usable on the physical channel 121 is selected for thetransmission 123 a-d. A TTI length may be defined as usable if thewireless device is able to transmit at that TTI, e.g. according to aconfiguration or capability of the wireless device. Examples may of thedisclosure may be defined without reference to TTI lengths being definedas usable.

The signal 107 may include a series of transmissions 123 a-d on aphysical channel 121 (e.g., sPUCCH) and a series of transmission 123 a-don the physical channel 121 (e.g., PUCCH) having a different TTI. AnsPUCCH may be referred to as a short or shortened PUCCH, a slot PUCCHfor 0.5 ms PUCCH, a subslot PUCCH for 1 ms/6 PUCCH, or the like. In onedefinition, an sPUCCH may refer to a PUCCH having a transmission timeinterval (TTI) that is less than a TTI of a normal PUCCH (e.g., LTERelease 8 PUCCH). For instance, a normal PUCCH has a TTI of onemillisecond and an sPUCCH has a TTI of 0.5 milliseconds. In anotherdefinition, an sPUCCH may have a TTI that is less than one millisecondor less than 0.5 milliseconds. The transmitted signal 107 from thewireless device may be considered as an uplink channel and/or a controlchannel (e.g. PUCCH or sPUCCH).

Aspects of the disclosure may provide a method in a wireless device ofperforming power control of a physical channel in a wirelesscommunication system. The wireless device 105 may determine atransmission power for a transmission on the physical channel (e.g.PUCCH or sPUCCH according to a power control loop. The loop specifiesthe transmission power based on at least one parameter. A value of theat least one parameter is dependent on which of different transmissiontime interval (TTI) lengths defined as usable on the physical channel isselected for the transmission on the physical channel. The value of theparameter may be dependent on the TTI length (e.g. 1 ms or a short TTIlength of less than 1 ms) of the transmission and/or a format of thetransmission. The value of the parameter may be determined by thewireless device e.g. based on configuration information received fromthe network node, and/or an indication of the value or informationallowing a determination of the value of the parameter which issignalled to the wireless device. Any option for communicating a valueof the parameter may be referred to as transmitting/receiving anindication of the value.

One such 1 ms TTI is constructed by using 14 OFDM or SC-FDMA symbols inthe case of normal cyclic prefix and 12 OFDM or SC-FDMA symbols in thecase of extended cyclic prefix. The shorter TTIs may have any durationin time and comprise resources on a number of OFDM or SC-FDMA symbolswithin a 1 ms subframe. As one example, the duration of the short TTImay be 0.5 ms, i.e. seven OFDM or SC-FDMA symbols, e.g. for the casewith normal cyclic prefix. As another example, the duration of the shortTTI may be 2 symbols, 3 symbols, etc, or a combination of differentshort TTI lengths.

In one definition, a power control loop allows a wireless device to setits transmit output power to a certain value. A power control loopincludes at least one of a closed power control loop and an open powercontrol loop. An open power control loop allows a wireless device to setits transmit output power to a certain value when the wireless device isaccessing a wireless communications network. A closed power control loopallows a wireless device to set its transmit output power to a certainvalue based on a transmit power control command received from a networknode.

In FIG. 1, the network node 101 may be configured to support one or morecommunication systems such as LTE, UMTS, GSM, NB-IoT, the like, or anycombination thereof. Further, the network node 101 may be a basestation, an access point, or the like. The network node 101 may servewireless device 105. The wireless device 105 may be configured tosupport one or more communication systems such as LTE, UMTS, GSM,NB-IoT, the like, or any combination thereof.

FIG. 2 illustrates one embodiment of a wireless device 200 forperforming power control of a physical channel in accordance withvarious aspects as described herein. In FIG. 2, the wireless device 200may include a transmission power determination circuit 201. Thetransmission power determination circuit 201 may be configured todetermine a transmission power for a transmission on the physicalchannel according to a power control loop. The loop may specify thetransmission power based on at least one parameter. Further, a value ofthe at least one parameter may be dependent on which of different TTIlengths defined as usable on the physical channel is selected for thetransmission on the physical channel.

In some aspects, the wireless device comprises a receiver circuitconfigured to receive, from a network node such as one that is servingthe wireless device 200, configuration information to allowdetermination of a value of the at least one parameter for one or morepower control loops for the physical channel. The value may be dependenton the TTI, i.e. different for different transmission time intervallengths. In some aspects, the wireless device comprises a transmittercircuit configured to transmit, to the network node, on the physicalchannel using the determined transmission power for the power controlloop.

FIG. 3 illustrates another embodiment of a wireless device 300 forperforming power control of a physical channel in accordance withvarious aspects as described herein. In FIG. 3, the wireless device 300may include processing circuit(s) 301, communications circuit(s) 305,antenna(s) 307, the like, or any combination thereof. The communicationcircuit(s) 305 may be configured to transmit or receive information toor from one or more network nodes or wireless devices via anycommunication technology. This communication may occur using the one ormore antennas 307 that are either internal or external to the wirelessdevice 300. The processing circuit(s) 301 may be configured to performprocessing as described herein (e.g., the method of FIG. 5 or 7) such asby executing program instructions stored in memory 303. The processingcircuit(s) 301 in this regard may implement certain functional means,units, or modules.

FIG. 4 illustrates another embodiment of a wireless device 400 forperforming power control of a physical channel in accordance withvarious aspects as described herein. In FIG. 4, the wireless device 400may implement various functional means, units, or modules (e.g., via theprocessing circuit(s) 301 in FIG. 3 or via software code). Thesefunctional means, units, or modules (e.g., for implementing the methodof FIG. 5 or 7) may include a transmission power determining module 403for determining a transmission power for a transmission on the physicalchannel according to a power control loop. The loop may specify thetransmission power based on at least one parameter. Further, a value ofthe at least one parameter may be dependent on which of different TTIlengths defined as usable on the physical channel is selected for thetransmission on the physical channel.

In some aspects, the wireless device 400 comprises functional means,units, or modules (e.g., for implementing the methods of FIGS. 5 and 7),including a receiving module or unit 401 for receiving, from a networknode, configuration information or signalling to determine a value of atleast one parameter for one or more loops for respective physicalchannels having different transmission time interval lengths. Inaddition, these functional means, units, or modules may include atransmitting module or unit for transmitting, to the network node, onthe physical channel the determined transmission power for the powercontrol loop.

FIG. 5 illustrates one embodiment of method 500 for performing powercontrol of a physical channel in accordance with various aspects asdescribed herein. In FIG. 5, the method 500 may start at, for instance,block 501 where it may determine a transmission power for a transmissionon the physical channel according to a power control loop. Further, theloop may specify the transmission power based on at least one parameter.Also, a value of the at least one parameter being dependent on which ofdifferent TTI lengths defined as usable on the physical channel isselected for the transmission on the physical channel. In a furtheraspect, the method 500 may include transmitting, by the wireless device,to the network node, on the physical channel using the determinedtransmission power.

FIG. 6 illustrates another embodiment of a wireless device 600 forperforming power control of a physical channel in accordance withvarious aspects as described herein. In some instances, the wirelessdevice 600 may be referred as a network node, a base station (BS), anaccess point (AP), a user equipment (UE), a mobile station (MS), aterminal, a cellular phone, a cellular handset, a personal digitalassistant (PDA), a smartphone, a wireless phone, an organizer, ahandheld computer, a desktop computer, a laptop computer, a tabletcomputer, a set-top box, a television, an appliance, a game device, amedical device, a display device, a metering device, or some other liketerminology. In other instances, the wireless device 600 may be a set ofhardware components. In FIG. 6, the wireless device 600 may beconfigured to include a processor 601 that is operatively coupled to aninput/output interface 605, a radio frequency (RF) interface 609, anetwork connection interface 611, a memory 615 including a random accessmemory (RAM) 617, a read only memory (ROM) 619, a storage medium 621 orthe like, a communication subsystem 631, a power source 633, anothercomponent, or any combination thereof. The storage medium 621 mayinclude an operating system 623, an application program 625, data 627,or the like. Specific devices may utilize all of the components shown inFIG. 6, or only a subset of the components, and levels of integrationmay vary from device to device. Further, specific devices may containmultiple instances of a component, such as multiple processors,memories, transceivers, transmitters, receivers, etc. For instance, acomputing device may be configured to include a processor and a memory.

In FIG. 6, the processor 601 may be configured to process computerinstructions and data. The processor 601 may be configured as anysequential state machine operative to execute machine instructionsstored as machine-readable computer programs in the memory, such as oneor more hardware-implemented state machines (e.g., in discrete logic,FPGA, ASIC, etc.); programmable logic together with appropriatefirmware; one or more stored-program, general-purpose processors, suchas a microprocessor or Digital Signal Processor (DSP), together withappropriate software; or any combination of the above. For example, theprocessor 601 may include two computer processors. In one definition,data is information in a form suitable for use by a computer. It isimportant to note that a person having ordinary skill in the art willrecognize that the subject matter of this disclosure may be implementedusing various operating systems or combinations of operating systems.

In the current embodiment, the input/output interface 605 may beconfigured to provide a communication interface to an input device,output device, or input and output device. The wireless device 600 maybe configured to use an output device via the input/output interface605. A person of ordinary skill will recognize that an output device mayuse the same type of interface port as an input device. For example, aUSB port may be used to provide input to and output from the wirelessdevice 600. The output device may be a speaker, a sound card, a videocard, a display, a monitor, a printer, an actuator, an emitter, asmartcard, another output device, or any combination thereof. Thewireless device 600 may be configured to use an input device via theinput/output interface 605 to allow a user to capture information intothe wireless device 600. The input device may include a mouse, atrackball, a directional pad, a trackpad, a presence-sensitive inputdevice, a display such as a presence-sensitive display, a scroll wheel,a digital camera, a digital video camera, a web camera, a microphone, asensor, a smartcard, and the like. The presence-sensitive input devicemay include a digital camera, a digital video camera, a web camera, amicrophone, a sensor, or the like to sense input from a user. Thepresence-sensitive input device may be combined with the display to forma presence-sensitive display. Further, the presence-sensitive inputdevice may be coupled to the processor. The sensor may be, for instance,an accelerometer, a gyroscope, a tilt sensor, a force sensor, amagnetometer, an optical sensor, a proximity sensor, another likesensor, or any combination thereof. For example, the input device may bean accelerometer, a magnetometer, a digital camera, a microphone, and anoptical sensor.

In FIG. 6, the RF interface 609 may be configured to provide acommunication interface to RF components such as a transmitter, areceiver, and an antenna. The network connection interface 611 may beconfigured to provide a communication interface to a network 643 a. Thenetwork 643 a may encompass wired and wireless communication networkssuch as a local-area network (LAN), a wide-area network (WAN), acomputer network, a wireless network, a telecommunications network,another like network or any combination thereof. For example, thenetwork 643 a may be a Wi-Fi network. The network connection interface611 may be configured to include a receiver and a transmitter interfaceused to communicate with one or more other nodes over a communicationnetwork according to one or more communication protocols known in theart or that may be developed, such as Ethernet, TCP/IP, SONET, ATM, orthe like. The network connection interface 611 may implement receiverand transmitter functionality appropriate to the communication networklinks (e.g., optical, electrical, and the like). The transmitter andreceiver functions may share circuit components, software or firmware,or alternatively may be implemented separately.

In this embodiment, the RAM 617 may be configured to interface via thebus 602 to the processor 601 to provide storage or caching of data orcomputer instructions during the execution of software programs such asthe operating system, application programs, and device drivers. In oneexample, the wireless device 600 may include at least one hundred andtwenty-eight megabytes (128 Mbytes) of RAM. The ROM 619 may beconfigured to provide computer instructions or data to the processor601. For example, the ROM 619 may be configured to be invariantlow-level system code or data for basic system functions such as basicinput and output (I/O), startup, or reception of keystrokes from akeyboard that are stored in a non-volatile memory. The storage medium621 may be configured to include memory such as RAM, ROM, programmableread-only memory (PROM), erasable programmable read-only memory (EPROM),electrically erasable programmable read-only memory (EEPROM), magneticdisks, optical disks, floppy disks, hard disks, removable cartridges,flash drives. In one example, the storage medium 621 may be configuredto include an operating system 623, an application program 625 such as aweb browser application, a widget or gadget engine or anotherapplication, and a data file 627.

In FIG. 6, the processor 601 may be configured to communicate with anetwork 643 b using the communication subsystem 631. The network 643 aand the network 643 b may be the same network or networks or differentnetwork or networks. The communication subsystem 631 may be configuredto include one or more transceivers used to communicate with the network643 b. For example, the communication subsystem 631 may be configured toinclude one or more transceivers used to communicate with one or moreremote transceivers of another wireless device such as a base station ofa radio access network (RAN) according to one or more communicationprotocols known in the art or that may be developed, such as IEEE802.xx, CDMA, WCDMA, GSM, LTE, UTRAN, WiMax, or the like.

In another example, the communication subsystem 631 may be configured toinclude one or more transceivers used to communicate with one or moreremote transceivers of another wireless device such as user equipmentaccording to one or more communication protocols known in the art orthat may be developed, such as IEEE 802.xx, CDMA, WCDMA, GSM, LTE,UTRAN, WiMax, or the like. Each transceiver may include a transmitter633 or a receiver 635 to implement transmitter or receiverfunctionality, respectively, appropriate to the RAN links (e.g.,frequency allocations and the like). Further, the transmitter 633 andthe receiver 635 of each transceiver may share circuit components,software or firmware, or alternatively may be implemented separately.

In the current embodiment, the communication functions of thecommunication subsystem 631 may include data communication, voicecommunication, multimedia communication, short-range communications suchas Bluetooth, near-field communication, location-based communicationsuch as the use of the global positioning system (GPS) to determine alocation, another like communication function, or any combinationthereof. For example, the communication subsystem 631 may includecellular communication, Wi-Fi communication, Bluetooth communication,and GPS communication. The network 643 b may encompass wired andwireless communication networks such as a local-area network (LAN), awide-area network (WAN), a computer network, a wireless network, atelecommunications network, another like network or any combinationthereof. For example, the network 643 b may be a cellular network, aWi-Fi network, and a near-field network. The power source 613 may beconfigured to provide an alternating current (AC) or direct current (DC)power to components of the wireless device 600.

In FIG. 6, the storage medium 621 may be configured to include a numberof physical drive units, such as a redundant array of independent disks(RAID), a floppy disk drive, a flash memory, a USB flash drive, anexternal hard disk drive, thumb drive, pen drive, key drive, ahigh-density digital versatile disc (HD-DVD) optical disc drive, aninternal hard disk drive, a Blu-Ray optical disc drive, a holographicdigital data storage (HDDS) optical disc drive, an external mini-dualin-line memory module (DIMM) synchronous dynamic random access memory(SDRAM), an external micro-DIMM SDRAM, a smartcard memory such as asubscriber identity module or a removable user identity (SIM/RUIM)module, other memory, or any combination thereof. The storage medium 621may allow the wireless device 600 to access computer-executableinstructions, application programs or the like, stored on transitory ornon-transitory memory media, to off-load data, or to upload data. Anarticle of manufacture, such as one utilizing a communication system maybe tangibly embodied in storage medium 621, which may comprise acomputer-readable medium.

The functionality of the methods described herein may be implemented inone of the components of the wireless device 600 or partitioned acrossmultiple components of the wireless device 600. Further, thefunctionality of the methods described herein may be implemented in anycombination of hardware, software or firmware. In one example, thecommunication subsystem 631 may be configured to include any of thecomponents described herein. Further, the processor 601 may beconfigured to communicate with any of such components over the bus 602.In another example, any of such components may be represented by programinstructions stored in memory that when executed by the processor 601performs the corresponding functions described herein. In anotherexample, the functionality of any of such components may be partitionedbetween the processor 601 and the communication subsystem 631. Inanother example, the non-computative-intensive functions of any of suchcomponents may be implemented in software or firmware and thecomputative-intensive functions may be implemented in hardware.

FIG. 7 illustrates another embodiment of method 700 by a wireless devicefor performing power control of physical channels in accordance withvarious aspects as described herein. In FIG. 7, the method 700 maystart, for instance, at block 701, where it includes receiving from anetwork node, a value of at least one parameter which is dependent onwhich of different transmission time interval lengths defined as usableon the physical channel is selected for the transmission on the physicalchannel. At block 703, the method 700 may include determining theransmission power for the physical channel based on the parameter. Atransmission power for a transmission on the physical channel isaccording to a power control loop, and wherein the power control loopspecifies the transmission power based on the parameter. At block 705,the method 700 may include transmitting, to the network node, on thephysical channel using the determined transmission power for the powercontrol loop.

FIG. 8 illustrates one embodiment of a network node 800 for performingpower control of physical channels (e.g. an uplink control channel) inaccordance with various aspects as described herein. In FIG. 8, thenetwork node 800 may include a receiver circuit 801, a determinationcircuit 803, a transmitter circuit 805, the like, or any combinationthereof. The determination circuit 803 may be configured to determine avalue of at least one parameter which is dependent on which of differenttransmission time interval lengths defined as usable on the physicalchannel is selected for the transmission on the physical channel. Atransmission power for a transmission by the wireless device on thephysical channel is according to a power control loop, and wherein thepower control loop specifies the transmission power based on theparameter.

The transmitter circuit 805 is configured to transmit, to the wirelessdevice, the value or an indication of the value or a configuration whichprovides the value, of the at least one parameter that corresponds tothe transmission powers for the transmissions by the wireless device onthe physical channel having the different transmission time intervallengths.

The receiver circuit 801 may be configured to receive, by the networknode, transmissions by the wireless device on the physical channel witheach transmission having a transmission power based on the one or moreparameters according to the corresponding power control loop.

FIG. 9 illustrates another embodiment of a network node 900 forperforming power control of physical channels in accordance with variousaspects as described herein. In FIG. 9, the network node 900 may includeprocessing circuit(s) 901, communications circuit(s) 905, antenna(s)907, the like, or any combination thereof. The communication circuit(s)905 may be configured to transmit or receive information to or from oneor more network nodes or one or more wireless devices via anycommunication technology. This communication may occur using the one ormore antennas 907 that are either internal or external to the networknode 900. The processing circuit(s) 901 may be configured to performprocessing as described herein (e.g., the method of FIG. 11) such as byexecuting program instructions stored in memory 903. The processingcircuit(s) 901 in this regard may implement certain functional means,units, or modules.

FIG. 10 illustrates another embodiment of a network node 1000 forperforming power control of physical channels in accordance with variousaspects as described herein. In FIG. 10, the network node 1000 mayimplement various functional means, units, or modules (e.g., via theprocessing circuit(s) 901 in FIG. 9 or via software code). Thesefunctional means, units, or modules (e.g., for implementing the methodof FIG. 11) may include a determining module or unit 1001 fordetermining a value of at least one parameter based on one or morereceived transmissions, from the wireless device, on the physicalchannel as described according to any example. Further, these functionalmeans, units, or modules include a transmitting module or unit 1003 fortransmitting, to the wireless device, the value of the at least oneparameter that corresponds to the transmission powers for thetransmissions by the wireless device on the physical channels having thedifferent transmission time interval lengths according to respectivepower control loops. In addition, these functional means, units, ormodules may include a receiving module or unit 1005 for receiving, fromthe wireless device, transmissions on each of the physical channels witheach transmission having a transmission power based on the one or moreparameters according to the corresponding power control loop.

FIG. 11 illustrates one embodiment of method 1100 performed by a networknode for performing power control of physical channels in accordancewith various aspects as described herein. In FIG. 11, the method 1100may start, for instance, at block 1101 where it may include, in anetwork node in a wireless communication system, determining a value ofat least one parameter which is dependent on which of differenttransmission time interval lengths defined as usable on the physicalchannel is selected for the transmission on the physical channel. Atransmission power for a transmission by the wireless device on thephysical channel is according to a power control loop, and wherein thepower control loop specifies the transmission power based on theparameter.

At block 1103, the method 1100 includes transmitting, to the wirelessdevice, the value or an indication of the value or a configuration whichprovides the value of the at least one parameter that corresponds to thetransmission powers for the transmissions by the wireless device on thephysical channels having the different transmission time intervallengths according to respective power control loops. At block 1105, themethod 1100 may include receiving, from the wireless device,transmissions on the physical channel with the transmission having atransmission power based on the one or more parameters according to thepower control loop including the determined parameter.

For purposes of illustration and explanation only, embodiments of thepresent disclosure may be described herein in the context of operatingin or in association with a RAN that communicates over radiocommunication channels with wireless devices, also interchangeablyreferred to as mobile terminals, wireless terminals, UEs and the like,using a particular radio access technology. More specifically,embodiments may be described in the context of the development ofspecifications for NB-IoT, particularly as it relates to the developmentof specifications for NB-IoT operation in spectrum or using equipmentcurrently used by E-UTRAN, sometimes referred to as the Evolved UMTSTerrestrial Radio Access Network and widely known as the LTE system.However, it will be appreciated that the techniques may be applied toother wireless networks, as well as to successors of the E-UTRAN. Thus,references herein to signals using terminology from the 3GPP standardsfor LTE should be understood to apply more generally to signals havingsimilar characteristics or purposes, in other networks. For example, aphysical resource block (PRB) herein comprises any physical or virtualtransmission resource or group of such transmission resources; that is,a physical resource block as used herein is not limited to a physicalresource block as defined in 3GPP standards.

A wireless device, as described herein, may be any type of wirelessdevice capable of communicating with a network node or another wirelessdevice (such as a user equipment, UE) over radio signals. In the contextof the present disclosure, it should be understood that a wirelessdevice may refer to a machine-to-machine (M2M) device, a machine-typecommunications (MTC) device, or an NB-IoT device. The wireless devicemay also be a UE, however it should be noted that the UE does notnecessarily have a “user” in the sense of an individual person owning oroperating the device. A wireless device may also be referred to as aradio device, a radio communication device, a wireless terminal, orsimply a terminal unless the context indicates otherwise, the use of anyof these terms is intended to include device-to-device UEs or devices,machine-type devices or devices capable of machine-to-machinecommunication, sensors equipped with a wireless device, wireless-enabledtable computers, mobile terminals, smart phones, laptop-embeddedequipped (LEE), laptop-mounted equipment (LME), USB dongles, wirelesscustomer-premises equipment (CPE), etc. In the discussion that follows,the terms machine-to-machine (M2M) device, machine-type communication(MTC) device, wireless sensor, and sensor may also be used. It should beunderstood that these devices may be UEs, but are generally configuredto transmit or receive data without direct human interaction.

In an IOT scenario, a wireless device as described herein may be, or maybe comprised in, a machine or device that performs monitoring ormeasurements, and transmits the results of such monitoring measurementsto another device or a network. Particular examples of such machines arepower meters, industrial machinery, or home or personal appliances, e.g.refrigerators, televisions, personal wearables such as watches etc. Inother scenarios, a wireless device as described herein may be comprisedin a vehicle and may perform monitoring or reporting of the vehicle'soperational status or other functions associated with the vehicle.

PUCCH can be used to carry different types of information: e.g. HARQfeedback, scheduling requests (SR), CQI feedback. Different PUCCHformats with different maximum payloads are defined to be able to carrythe different information types.

PUCCH format 1/1a/1b is suitable for transmitting HARQ feedback andscheduling requests (SR).

PUCCH format 2 is dedicated to the transmission of CQI reports. PUCCHformat 3 supports the HARQ feedback for multiple carrier components whencarrier aggregation is configured for a UE. It can be expected thatdifferent formats with different maximum payloads will be supported forsPUCCH.

Power control for PUCCH is defined in 3GPP TS 36.213 as, for subframe iand serving cell c,

${P_{PUCCH}(i)} = {\min\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{P_{0\_\;{PUCCH}} + {PL}_{c} + {h\left( {n_{CQI},n_{HARQ},n_{SR}} \right)} +} \\{{\Delta_{F\;\_\;{PUCCH}}(F)} + {\Delta_{TxD}\left( F^{\prime} \right)} + {g(i)}}\end{matrix}\end{Bmatrix}}$for PUCCH format 1/1a/1b/2/2a/2b/3 and

${P_{PUCCH}(i)} = {\min\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{P_{0{\_ PUCCH}} + {PL}_{c} + {10\log_{10}\left( {M_{{PUCCH},c}(i)} \right)} +} \\{{\Delta_{{TF},c}(i)} + {\Delta_{F\_ PUCCH}(F)} + {g(i)}}\end{matrix}\end{Bmatrix}}$for PUCCH format 4/5,where

-   -   P_(CMAX,c)(i) is the maximum transmit power.    -   P_(O_PUCCH) is the target of received power.    -   PL_(c) is the downlink path loss estimate.    -   h(n_(CQI),n_(HARQ),n_(SR)) is a PUCCH format dependent value        that reflects cases with larger payload.    -   M_(PUCCH,c)(i) is the number of resource blocks for PUCCH format        5, equals 1 for all other formats.    -   Δ_(F_PUCCH)(F) is a relation in dB between PUCCH format F and        PUCCH format 1a.    -   Δ_(TF,c)(i) is an adjustment factor depending on number of coded        bits that is exactly specified in 3GPP TS36.213.    -   Δ_(T×D)(F′) depends on the number of antenna ports configured        for PUCCH.    -   g(i) is the closed loop power control state and is updated using        δ_(PUCCH) signalled in the downlink assignment.

Apparatus and method to support power control of an uplink controlchannel, in particular, sPUCCH transmissions are described below. Theseprovide for power control to be achieved in a simple and efficientmanner.

sPUCCH is the short TTI equivalent of PUCCH. In some examples, therewill be at least one format of sPUCCH defined for each supported UL TTIlength. Example UL TTI lengths are 2, 4 and 7 SC-FDMA symbols, althoughthe TTI may contain other numbers of symbols. The formats selected forsPUCCH may be based on existing formats of PUCCH. Link level simulationsperformed highlight that independently of the selected sPUCCH format(s),a larger SNR is required for sPUCCH compared to PUCCH in order to reachsimilar performance e.g. in terms of ACK missed detection probability,NACK-to-ACK error probability and/or DTX-to-ACK probability. The shorterthe sPUCCH length, the larger is the performance gap relative to PUCCH.The sPUCCH power control addresses this performance gap for UEs that arenot power-limited. References to PUCCH or sPUCCH may alternatively bereferred to as an uplink control channel.

The above closed loop power control equations may be applied to sPUCCH,with the modifications described below. The closed loop power controlstate, g(i), for PUCCH is derived from the Transmit Power Control, TPC,information δ_(PUCCH) signalled to the wireless device 300;400, e.g. inthe downlink assignment for 1 ms TTI. For fast closed loop power controlof sPUCCH, δ_(PUCCH) may also be signalled for sPUCCH in the downlinkassignment for sTTI. The power control of transmissions according to theexamples described may be carried out by a wireless device 105, 200,300, 400, 600 according to any example. An indication of the value ofone or parameter (which may be by providing configuration information)may be transmitted to the wireless device from a network node accordingto any example of network node 800;900;1000. The performance differencemay be captured in Δ_(F_PUCCH)(F) that is signaled from higher layers.The performance difference is format-dependent and also TTI lengthdependent, and so in some examples, a complementary parameter is used.In addition to what is described below, h(n_(CQI),n_(HARQ),n_(SR)) andΔ_(TF,c)(i) are defined for sTTI formats and TTI lengths. The referenceformat for sPUCCH is proposed to be PUCCH format 1a. In the following,several options for sPUCCH power control are considered.

In some aspects, a method or wireless device are provided fordetermining a transmission power for a transmission on the physicalchannel according to a power control loop, wherein the loop specifiesthe transmission power based on at least one parameter. A value of theat least one parameter is dependent on which of different transmissiontime interval (TTI) lengths defined as usable (e.g. a short TTI) on thephysical channel is selected for the transmission on the physicalchannel. In some examples, the at least one parameter has a differentvalue for each TTI length usable on the physical channel. In someexamples, the value of the at least one parameter further depends onwhich of different transmission formats defined as usable on thephysical channel is selected for the transmission on the physicalchannel. In some examples, the at least one parameter has a differentvalue for each transmission format usable on the physical channel.

In a first embodiment, a power control parameter Δ_(F_PUCCH)(F) isdefined for the different formats and TTI lengths of sPUCCH. If thesPUCCH formats are defined as standalone formats and added to thecurrent list of PUCCH formats existing today, then this provides aneffective control of the desired transmission power of sPUCCH. Thedifferent TTI lengths of the sPUCCHs may be considered as part of theformat. A new Δ_(F_PUCCH)(F) may be defined for each new format, i.e.for each new variant of selected legacy format types and TTI length.

In some example sTTI formats, frequency hopping is not used. In order toalleviate the loss of frequency diversity, a constant term can be addedto the formats without frequency hopping.

In a further embodiment, a power control parameter Δ_(F_PUCCH)(F) isdefined for the different formats of sPUCCH. A further, new, powercontrol parameter depending on the TTI length is introduced and added tothe other parameters in the power control formulas. In this example, thenew sPUCCH formats may be defined as based on the legacy formats, butwith different TTI lengths. This example may provide for moretransparency for the case described above without frequency hopping.

In some aspects, a new value of the parameter Δ_(F_PUCCH)(F) would thenbe defined for each format type, e.g. each new variant of selectedlegacy format types, and this new Δ_(F_PUCCH)(F) is common to all shortTTI lengths, e.g. shorter than the 1 ms TTI. Additionally, a new powercontrol parameter Δ_(TTI)(TTI length) is defined to refine the poweradjustment for each possible TTI length. The power control parameterΔ_(TTI)(TTI length) is included in the above power control equationswith the instance of Δ_(F_PUCCH)(F). Note that this requires that a TTIlength change affects the required power for all formats equally. Oneway of defining the parameters is that Δ_(F_PUCCH)(F) is defined by agiven sTTI length. The parameter Δ_(TTI)(TTI length), which has a valuewhich is TTI length dependent, applies for all other sTTI lengths. Insome aspects, Δ_(TTI)(TTI length) may be a scaling factor depending onthe sTTI length and is not a configurable parameter.

In some aspects, the value of the at least one parameter is based on apower adjustment for the transmission on the physical channel having theselected TTI length. Any of the parameters described may be consideredas providing a power adjustment.

In some aspects, the value of the at least one parameter is based on aratio of a power adjustment for the transmission on the physical channelhaving the selected TTI length (e.g. sTTI) and a power adjustment forthe transmission on the physical channel having a predetermined TTIlength (e.g. 1 ms TTI). Thus, the value of the parameter, which may beany parameter described, provides for the same power in sPUCCH for thesTTI as for the PUCCH for the 1 ms TTI. In any example, the selected TTIlength may be a short TTI or a 1 ms TTI e.g. having 14 symbols.

In some aspects, the value any of the power control parameters is basedon a number of symbols in the transmission on the physical channelhaving the selected TTI length (e.g. sTTI length). In some aspects, thevalue of the at least one parameter (power control parameter) is basedon a ratio of a number of symbols in a transmission on the physicalchannel having the selected TTI length (sTTI) and a number of symbols ina transmission on the physical channel having a predetermined TTI length(1 ms TTI). In some aspects, the ratio, e.g. defining the parameterΔ_(TTI)(TTI length), is represented as:

${10{\log_{10}\left( \frac{{TTIsymbols}_{selected}}{{TTIsymbols}_{predetermined}} \right)}},$

wherein TTIsymbols_(selected) is the selected number of TTI symbols(e.g. sTTI), and TTIsymbols_(predetermined) is the predetermined numberof TTI symbols (e.g. in 1 ms TTI). The parameter may alternatively beexpressed in terms of length of time rather in terms of symbols as:

${10{\log_{10}\left( \frac{{TTIlength}_{selected}}{{TTIlength}_{predetermined}} \right)}},$wherein TTIlength_(selected) is the selected TTI length, andTTIlength_(predetermined) is the predetermined TTI length.

In a version of this embodiment,

${\Delta_{TTI}\left( {{TTI}\mspace{14mu}{length}} \right)} = {10\;\log_{10}{\frac{{TTI}\mspace{14mu}{length}}{14}.}}$TTI length here is the number of symbols in the (s)TTI. This providesthat the received energy (i.e. power) of the sPUCCH format is the sameas for the legacy PUCCH format having 14 symbols.

In a further example, it is noted that some OFDM symbols in a PUCCHtransmission are used for sending pilots, and others are used forsending Uplink Control Information, UCI. In some aspects, it might bebeneficial to more closely compensate for the different energyrequirements for channel estimation and decoding.

Therefore, a refinement of the above formula for a parameter, e.g.Δ_(TTI)(TTI length) may be (or include a ratio):

${a\; 10{\log_{10}\left( \frac{{TTIpilotsymbols}_{selected}}{{TTIpilotsymbols}_{predetermined}} \right)}} + {b\; 10{\log_{10}\left( \frac{{TTIcontrolsymbols}_{selected}}{{TTIcontrolsymbols}_{predetermined}} \right)}}$wherein the selected number of TTI symbols corresponds to a selectednumber of pilot symbols (TTIpilotsymbols_(selected)) and a selectednumber of control symbols (TTIcontrolsymbols_(selected)), and thepredetermined number of TTI symbols corresponds to a predeterminednumber of pilot symbols (TTIpilotsymbols_(predetermined)) and apredetermined number of control symbols(TTIcontrolsymbols_(predetermined)), wherein a and bare constants.

An equivalent for TTI length in time may be expressed as:

${{a\; 10{\log_{10}\left( \frac{{TTIpilotlength}_{selected}}{{TTIpilotlength}_{predetermined}} \right)}} + {b\; 10{\log_{10}\left( \frac{{TTIcontrollength}_{selected}}{{TTIcontrollength}_{predetermined}} \right)}}},$wherein the selected TTI length corresponds to a selected pilot symbolslength (TTIpilotlength_(selected)) and a selected control symbols length(TTIcontrollength_(selected)), wherein the predetermined TTI lengthcorresponds to a predetermined pilot symbols length(TTIpilotlength_(predetermined)) and a predetermined control symbolslength (TTIcontrollength_(predetermined)), and wherein a and bareconstants.

In some aspects, this expression may alternatively be defined as:

${{\Delta_{TTI}\left( {{TTI}_{p},{TTI}_{UCI}} \right)} = {{a\; 10\log_{10}\frac{{TTI}_{p}}{{Ref}_{p}}} + {b\; 10\;\log_{10}\frac{{TTI}_{UCI}}{Ref\_ UCI}}}},$where Ref_UCI and Ref p are the number of OFDM symbols used for UCI andfor pilots for a reference format, respectively. For example, if PUCCHFormat 4 is the reference format, Ref p=2, and Ref UCI=12. The values aand b are constants that can be used to configure, or weight, theimportance of channel estimation versus decoding performance. For PUCCHformats 1a/1b used for reference, Ref p=6, and Ref UCI=8.

In an embodiment, Δ_(F_PUCCH)(F) is defined for the different formats ofsPUCCH. New vales of the target of received powers P_(O_PUCCH) aredefined for the different TTI lengths. The new sPUCCH formats will havedifferent target of received powers than the current PUCCH formats,primarily because of the different TTI lengths. This could be captured,or included, in new (i.e. modified) values of the power controlparameter P_(O_PUCCH) for the sPUCCH formats. In some aspects, this maybe used if the sPUCCH formats are defined in such a way that the targetof received power differs substantially from the target of receivedpower for 1 ms TTI (i.e. as used today). In some aspects, the sameamount of new, i.e. modified, power control parameter Δ_(F_PUCCH) may bedefined as in the first embodiment above. In a variant of thisembodiment, the same target of received power P_(O_PUCCH) is used fordifferent sTTI lengths, and a TTI-length dependent received power offsetP_(O_PUCCH_OFFSET) is added to the power control equation with thetarget of received power.

In an embodiment, even though the above alternatives are listed inseparate embodiments, it is also an alternative to combine differentembodiments to provide a solution. Note in particular that theembodiment including

${\Delta_{TTI}\left( {{TTI}\mspace{14mu}{length}} \right)} = {10\;\log_{10}\frac{{TTI}\mspace{14mu}{length}}{14}}$above requires a reference format, and may fit well into a term whichdepends on the sPUCCH format.

In another embodiment, the techniques described herein may be appliedfor a transmission duration based on a two-symbol sTTI, four-symbolsTTI, and one-slot sTTI for sPUCCH/sPUSCH, where down-selection is notprecluded.

In another embodiment, the techniques described herein may be appliedfor an LTE frame structure type 2, which specifies support for atransmission duration based on a one-slot sTTI forsPDSCH/sPDCCH/sPUSCH/sPUCCH.

A power control methodology for sPUSCH and sPUCCH for sTTI is describedbelow. Power control for PUSCH for subframe i and serving cell C isdefined as follows:

${{P_{{PUSCH},c}(i)} = {\min\begin{Bmatrix}{{10{\log_{10}\left( {{{\hat{P}}_{{CMAX},c}(i)} - {{\hat{P}}_{PUCCH}(i)}} \right)}},} \\\begin{matrix}{{10{\log_{10}\left( {M_{{PUSCH},c}(i)} \right)}} + {P_{{O\_ PUSCH},c}(j)} +} \\{{{\alpha_{c}(j)} \cdot {PL}_{c}} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{matrix}\end{Bmatrix}}},$where:{circumflex over (P)}_(CMAX,c)(i) is the maximum transmit power inlinear scale;{circumflex over (P)}_(PUCCH)(i) is the power of simultaneouslytransmitted PUCCH in linear scale, is equal to zero if no PUCCH istransmitted;M_(PUSCU,c)(i) is the number of resource blocks;P_(O_PUSCH,c)(j) is the target of received power signaled to the UE overRRC;α_(c)(j)·PL_(c) is the scaled downlink path loss estimate, with0≤α_(c)(j)≤1 signaled to the UE over RRC;Δ_(TF,c)(i) is an adjustment factor depending on number of coded bits;andf_(c)(i) is the closed loop power control derived from what is signaledto the UE in the uplink grant.

Assuming a fixed allocated bandwidth for all TTI lengths and that thetransport block size (TBS) is scaled linearly with the TTI length, acomparison of performance between PUSCH and sPUSCH indicates that 10%block error rate (BLER) is achieved at a similar signal-to-noise ratio(SNR) for sPUSCH and PUSCH. This means that using the same targetreceived power level for sPUSCH as for PUSCH leads to similar sPUSCH andPUSCH performance.

Accordingly, PUSCH and sPUSCH have the same or similar performanceassuming a fixed allocated bandwidth and a linearly scaled TBS with theTTI length. As a consequence, sPUSCH may be power controlled in the sameway as PUSCH. The following equation shows how the power control forsPUSCH transmission in short TTI i would look like if a UE is not powerlimited. The power control parameters configured over RRC for PUSCH maybe reused for sPUSCH. This means that the parameters P_(O_PUSCH,c)(j)and α_(c)(j) configured over RRC for PUSCH transmission are applied inthe power control equation for sPUSCH according to:P _(sPUSCH,c)(i)=10 log₁₀(M _(sPUSCH,c)(i))+P_(O_PUSCH,c)(j)+α_(c)(j)·PL _(c)+Δ_(TF,c)(i)+f _(c)(i).

Accordingly, sPUSCH should be power controlled in the same way as PUSCH,with the same parameters configured over RRC.

Regarding the closed loop parameter (f_(c)) that is calculated based onTPC information δ_(PUSCH) contained in the uplink grant for onemillisecond TTI, there may be a benefit to signal it in each uplinkgrant for sTTI so as to be able to faster correct the UE power andconverge to the appropriate value. As such, TPC information used toupdate the closed loop component of the uplink power control (f_(c)) isincluded in the uplink grant of uplink sTTI.

Two methods exist today to calculate f_(c): accumulation activated ornot activated. If accumulation is not activated, f_(c)(i) followsdirectly the value of δ_(PUSCH) indicated in the uplink grant. Thismethod may be easily extended for the case of sTTI. If accumulation isactivated, f_(c)(i) is updated according to δ_(PUSCH) in the uplinkgrant and its previous value f_(c)(i−1) according to:f _(c)(i)=f _(c)(i−1)+δ_(PUSCH,c)(i−K _(PUSCH)).

K_(PUSCH) represents the delay between the uplink grant and the uplinkdata transmission (transmission). With δ_(PUSCH) included in the uplinkgrant for sTTI, the accumulation happens more frequently than on amillisecond basis. Thus, the UE power converges faster to the intendedvalue, which is beneficial.

Short TTI UEs may be scheduled dynamically with a subframe to subframegranularity with PUSCH and/or sPUSCH. Since the accumulation-basedmethod makes f_(c)(i) dependent of its previous value f_(c)(i−1), itshould be considered whether the calculation of f_(c)(i) for a onemillisecond uplink TTI that follows immediately a uplink sTTI should bebased on the f_(c) value used for this uplink sTTI and vice-versa. Inother words, a one millisecond uplink TTI and uplink sTTI share the sameparameter for the closed loop correction f_(c).

Separate closed loop correction between different TTI lengths is analternative. However, if the uplink power control equation of PUSCH isreused for sPUSCH with the same RRC configured parameters, there is noreason to have separate closed loop components f_(c) one valid for onemillisecond TTI and another valid for short TTI. In fact, with a commonclosed loop component f_(c) for both one millisecond uplink TTI anduplink sTTI, the power used for one millisecond TTI may benefit from thefaster convergence of f_(c) to the most appropriate value due to uplinksTTI usage.

Accordingly, a shared closed loop component f_(c) is used for uplinkpower control of one millisecond TTI and sTTI. However, situations likethe one depicted in FIG. 12 may happen where uplink grants for one ormore uplink sTTIs are sent after the uplink grant for a one millisecondTTI. Since the delay between the uplink grant for uplink sTTI and theuplink sTTI transmission is shorter than the one between the uplinkgrant for one millisecond TTI and the one millisecond uplink TTItransmission, the value for δ_(PUSCH) indicated in the uplink grant ofone millisecond TTI becomes obsolete.

Consider the example in FIG. 12 with an initial value f_(c,init), thecommand in the uplink grant for one millisecond TTI intends to achievean uplink power corrected by f_(c,init)+3 dB. In the meantime, uplinksTTIs are scheduled and δ_(PUSCH) is signaled in the uplink grant forsTTI as well. In this example, the first uplink sTTI transmissionapplies a closed loop component of f_(c,init)+3 dB. The eNB thenobserves that the correction of +3 dB was not accurate enough and sendsa further correction in the uplink grant for the second uplink sTTI. Theclosed loop component for the second uplink sTTI is corrected tof_(c,init)+3 dB−1 dB. In this example, if the UE follows the δ_(PUSCH)sent in the uplink grant of the one millisecond TTI, the closed loopcomponent would reach f_(c,init)+3 dB−1 dB+3 dB. Instead, it appearsmore reasonable that the UE ignores the old δ_(PUSCH), sent in theuplink grant of one millisecond TTI if δ_(PUSCH) commands were receivedin uplink short TTI grants afterwards and if the calculation of f_(c)(i)is accumulation-based.

Accordingly, if the calculation of f_(c)(i) is accumulation-based, theUE ignores a δ_(PUSCH) sent in the uplink grant of one millisecond TTIif δ_(PUSCH) commands were received in uplink short TTI grantsafterwards.

Note that while the power control mechanism for PUSCH and sPUSCH areproposed to be the same, they both are indirectly affected by theintroduction of sPUCCH power control since the meaning of {circumflexover (P)}_(PUCCH)(i) will change or a new parameter {circumflex over(P)}_(sPUCCH)(i) needs to be introduced with similar mechanism.

Power control for PUCCH formats 1/1a/1b/2/2a/2b/3 for subframe i andserving cell C is described as follows:

${{P_{PUCCH}(i)} = {\min\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{P_{0{\_ PUCCH}} + {PL}_{c} + {h\left( {n_{CQI},n_{HARQ},n_{SR}} \right)} +} \\{{\Delta_{F\_ PUCCH}(F)} + {\Delta_{TxD}\left( F^{\prime} \right)} + {g(i)}}\end{matrix}\end{Bmatrix}}},$where:P_(CMAX,c)(i) is the maximum transmit power;P_(O_PUCCH) is the target of received power;PL_(c) is the downlink path loss estimate;h(n_(CQI),n_(HARQ),n_(SR)) is a PUCCH format dependent value thatreflects cases with larger payload;M_(PUCCH,c)(i) is the number of resource blocks for PUCCH format 5,equals one for all other formats;Δ_(F_PUCCH)(F) is a relation in dB between PUCCH format F and PUCCHformat 1a;Δ_(TF,c)(i) is an adjustment factor depending on number of coded bits;Δ_(T×D)(F′) depends on the number of antenna ports configured for PUCCH;andg(i) is the closed loop power control state and is updated usingδ_(PUCCH) signaled in the downlink assignment.

Power control for PUCCH formats 4/5 for subframe i and serving cell C isdescribed as follows:

${P_{PUCCH}(i)} = {\min{\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{P_{0{\_ PUCCH}} + {PL}_{c} + {10{\log_{10}\left( {M_{{PUCCH},c}(i)} \right)}} +} \\{{\Delta_{{TF},c}(i)} + {\Delta_{F\_ PUCCH}(F)} + {g(i)}}\end{matrix}\end{Bmatrix}.}}$

There may be at least one format of sPUCCH defined for each supporteduplink TTI length. The uplink TTI lengths may be any number of symbols.For instance, the uplink TTI lengths may be two, four, and seven SC-FDMAsymbols. Independent of the selected sPUCCH format(s), a larger SNR maybe required for sPUCCH compared to PUCCH in order to reach similarperformance in terms of ACK missed detection probability, NACK-to-ACKerror probability, DTX-to-ACK probability, and the like. The shortersPUCCH is relative to PUCCH, the larger the performance gap betweensPUCCH and PUCCH. So, the sPUCCH power control needs to address thisperformance gap for UEs that are not power-limited. The closed loopstate (g(i)) for PUCCH is derived from the TPC information δ_(PUCCH)signaled in the downlink assignment for one millisecond TTI. For fastclosed loop power control of sPUCCH, it would be convenient to alsosignal δ_(PUCCH) for sPUCCH in the downlink assignment for sTTI. A wayto capture the performance difference in Δ_(F_PUCCH)(F) that is signaledfrom higher layers. However, since the performance difference is notonly format-dependent but also TTI length dependent, a complementaryparameter may be needed. In the following, several options for sPUCCHpower control are considered.

In one embodiment, Δ_(F_PUCCH)(F) is defined for the different formatsand TTI lengths of sPUCCH. If the new sPUCCH formats are defined asstandalone formats and added to the current list of PUCCH formatsexisting today, then this is the straight forward approach to describethe desired power of sPUCCH. The different TTI lengths of the sPUCCHsmay then simply be considered as part of the format. A newΔ_(F_PUCCH)(F) would then be defined for each new format (e.g., for eachnew variant of selected legacy format types and TTI length).

In another embodiment, Δ_(F_PUCCH)F) is defined for the differentformats of sPUCCH. A new parameter depending on the TTI length isintroduced and added to the other parameters in the power controlformulas. If the new sPUCCH formats are defined as based on the legacyformats, but with different TTI lengths, or if more transparency isdesired, then this is a logical way forward. A new Δ_(F_PUCCH)(F) wouldthen be defined for each new format (e.g., for each new variant ofselected legacy format types). Additionally, a new parameterΔ_(TTI)(TTI−length) would need to be defined for each possible TTIlength. Note that this requires that a TTI length change affects therequired power for all formats equally.

In another embodiment, Δ_(F_PUCCH)(F) is defined for the differentformats of sPUCCH. New target received powers P_(O_PUCCH) are definedfor different TTI lengths. The new sPUCCH formats will have differenttarget received powers than the current PUCCH formats, mostly because ofthe different TTI lengths. This may be captured in new P_(O_PUCCH) forthe new sPUCCH formats. If the sPUCCH formats are defined in such a waythat the target received power differs much from the target receivedpower used today this is an alternative. Note that this would mostlikely still result in the need to define the same amount of newΔ_(F_PUCCH)(F).

Additionally, h(n_(CQI),n_(HARQ),n_(SR)) and Δ_(TF,c)(i) needs to bedefined for new formats and TTI lengths.

The reference format for sPUCCH is proposed to be PUCCH format 1a. Someother reference format may be selected, but that would only make thingsmore complicated.

For power prioritization within each different sTTI length, the sameprioritization as for one millisecond TTI should be re-used.Accordingly, the power prioritization within each different sTTI lengthmay be the same as for one millisecond TTI.

Since sTTI is used to reduce latency, it is also possible to prioritizesTTI over one millisecond TTI since that will to the furthest extentmake sure that latency critical sTTI transmissions are carried out assoon as possible. Accordingly, with respect to power, sTTI may beprioritized over one millisecond TTI.

Prioritizing sTTI transmissions over one millisecond TTI transmissionsmay potentially ruin the one millisecond TTI transmission if the sTTItransmission is scheduled in the same subframe as the one millisecondTTI transmission and the UE is power limited. Because of this, if the UEis power limited it may not use multiple carriers together with sTTI.Accordingly, power limited UEs may not use multiple carriers togetherwith sTTI.

In LTE, there are two different types of power headroom reports defined.Type 1 assumes PUSCH only transmission and type 2 assumes PUSCH andPUCCH transmission. The power headroom is in both cases defined persubframe and carrier as:Power Headroom=Maximum allowed power−Estimated desired power

The Maximum allowed power is the configured maximum power. The Estimateddesired power is the ideal power to use for the current modulation,coding scheme, channel, or the like, assuming no restrictions intransmit power. As per definition, the power headroom may becomenegative if the UE is power limited. The power headroom report istransmitted by the UE together with the message, the report is triggeredin the uplink grant.

The current definition of power headroom applies also to sTTI using theestimated desired power. Accordingly, the power headroom for sTTI may becalculated using the same principle as for one millisecond TTI using thedesired power for the sTTI transmission. Further, the power headroomreport if transmitted in sTTI may be based on sTTI transmission of thatspecific sTTI length.

As the ON/OFF periods in uplink will be shorter due to the shorteruplink TTI lengths, the ON/OFF and OFF/ON transient periods will benoticeable. These transient periods are defined to each be below 20μsec., 2% of the subframe length. In practice due to the 20 μsec. ON/OFFtransient period, the SC-FDMA symbols preceding and following an uplinktransmission may not be usable for data transmission, see FIG. 13. Withtwo symbols TTI length (i.e., 1/7 of the original length), each 20 μsperiod is now about 14% of the TTI length. As implementations typicallyperform significantly better than the 20 μs requirement, the ON/OFF timemasks should be tightened to improve the short TTI transmission.Accordingly, absolute ON/OFF time masks may be tightened for short TTIlengths.

Abbreviations:

Abbreviation Explanation

BLER Block Error Rate

CP Cyclic Prefix

DCI Downlink Control Information

DTX Discontinuous Transmission

ePDCCH enhanced Physical Downlink Control Channel

HTTP Hypertext Transfer Protocol

LTE Long Term Evolution

MAC Medium Access Control

MCS Modulation and Coding Scheme

OFDM Orthogonal Frequency Division Multiple Access

PDCCH Physical Downlink Control Channel

PDSCH Physical Downlink Shared Channel

PRB Physical Resource Block

PUCCH Physical Uplink Control Channel

PUSCH Physical Uplink Shared Channel

RAT Radio Access Technology

RB Resource Block

RE Resource Element

RRC Radio Resource Control

SC-FDMA Single Carrier-Frequency Division Multiple Access

sPDCCH short Physical Downlink Control Channel

sPDSCH short Physical Downlink Shared Channel

sPUCCH short Physical Uplink Control Channel

sPUSCH short Physical Uplink Shared Channel

SF SubFrame

TCP Transmission Control Protocol

TTI Transmission Time Interval

sTTI short Transmission Time Interval

UCI Uplink Control Information

UL Uplink

The previous detailed description is merely illustrative in nature andis not intended to limit the present disclosure, or the application anduses of the present disclosure. Furthermore, there is no intention to bebound by any expressed or implied theory presented in the precedingfield of use, background, summary, or detailed description. The presentdisclosure provides various examples, embodiments and the like, whichmay be described herein in terms of functional or logical blockelements. The various aspects described herein are presented as methods,devices (or apparatus), systems, or articles of manufacture that mayinclude a number of components, elements, members, modules, nodes,peripherals, or the like. Further, these methods, devices, systems, orarticles of manufacture may include or not include additionalcomponents, elements, members, modules, nodes, peripherals, or the like.

Furthermore, the various aspects described herein may be implementedusing standard programming or engineering techniques to producesoftware, firmware, hardware (e.g., circuits), or any combinationthereof to control a computing device to implement the disclosed subjectmatter. It will be appreciated that some embodiments may be comprised ofone or more generic or specialized processors such as microprocessors,digital signal processors, customized processors and field programmablegate arrays (FPGAs) and unique stored program instructions (includingboth software and firmware) that control the one or more processors toimplement, in conjunction with certain non-processor circuits, some,most, or all of the functions of the methods, devices and systemsdescribed herein. Alternatively, some or all functions could beimplemented by a state machine that has no stored program instructions,or in one or more application specific integrated circuits (ASICs), inwhich each function or some combinations of certain of the functions areimplemented as custom logic circuits. Of course, a combination of thetwo approaches may be used. Further, it is expected that one of ordinaryskill, notwithstanding possibly significant effort and many designchoices motivated by, for example, available time, current technology,and economic considerations, when guided by the concepts and principlesdisclosed herein will be readily capable of generating such softwareinstructions and programs and ICs with minimal experimentation.

The term “article of manufacture” as used herein is intended toencompass a computer program accessible from any computing device,carrier, or media. For example, a computer-readable medium may include:a magnetic storage device such as a hard disk, a floppy disk or amagnetic strip; an optical disk such as a compact disk (CD) or digitalversatile disk (DVD); a smart card; and a flash memory device such as acard, stick or key drive. Additionally, it should be appreciated that acarrier wave may be employed to carry computer-readable electronic dataincluding those used in transmitting and receiving electronic data suchas electronic mail (e-mail) or in accessing a computer network such asthe Internet or a local area network (LAN). Of course, a person ofordinary skill in the art will recognize many modifications may be madeto this configuration without departing from the scope or spirit of thesubject matter of this disclosure.

Throughout the specification and the embodiments, the following termstake at least the meanings explicitly associated herein, unless thecontext clearly dictates otherwise. Relational terms such as “first” and“second,” and the like may be used solely to distinguish one entity oraction from another entity or action without necessarily requiring orimplying any actual such relationship or order between such entities oractions. The term “or” is intended to mean an inclusive “or” unlessspecified otherwise or clear from the context to be directed to anexclusive form. Further, the terms “a,” “an,” and “the” are intended tomean one or more unless specified otherwise or clear from the context tobe directed to a singular form. The term “include” and its various formsare intended to mean including but not limited to. References to “oneembodiment,” “an embodiment,” “example embodiment,” “variousembodiments,” and other like terms indicate that the embodiments of thedisclosed technology so described may include a particular function,feature, structure, or characteristic, but not every embodimentnecessarily includes the particular function, feature, structure, orcharacteristic. Further, repeated use of the phrase “in one embodiment”does not necessarily refer to the same embodiment, although it may. Theterms “substantially,” “essentially,” “approximately,” “about” or anyother version thereof, are defined as being close to as understood byone of ordinary skill in the art, and in one non-limiting embodiment theterm is defined to be within 10%, in another embodiment within 5%, inanother embodiment within 1% and in another embodiment within 0.5%. Adevice or structure that is “configured” in a certain way is configuredin at least that way, but may also be configured in ways that are notlisted.

The invention claimed is:
 1. A method of performing power control of aphysical channel in a wireless communication system, the methodcomprising a wireless device: determining a transmission power for atransmission on the physical channel according to a power control loop;wherein the loop specifies the transmission power based on at least oneparameter, with a value of the at least one parameter being dependent onwhich of different transmission time interval (TTI) lengths defined asusable on the physical channel is selected for the transmission on thephysical channel.
 2. The method of claim 1, wherein the at least oneparameter has a different value for each TTI length usable on thephysical channel.
 3. The method of claim 1, wherein the value of the atleast one parameter further depends on which of different transmissionformats defined as usable on the physical channel is selected for thetransmission on the physical channel.
 4. The method of claim 3, whereinthe at least one parameter has a different value for each transmissionformat usable on the physical channel.
 5. The method of claim 1, whereinthe value of the at least one parameter is based on a power adjustmentfor the transmission on the physical channel having the selected TTIlength.
 6. The method of claim 1, wherein the value of the at least oneparameter is based on a ratio of a power adjustment for the transmissionon the physical channel having the selected TTI length and a poweradjustment for the transmission on the physical channel having apredetermined TTI length.
 7. The method of claim 1, wherein the value ofthe at least one parameter is based on a number of symbols in thetransmission on the physical channel having the selected TTI length. 8.The method of claim 1, wherein the value of the at least one parameteris based on a ratio of a number of symbols in a transmission on thephysical channel having the selected TTI length and a number of symbolsin a transmission on the physical channel having a predetermined TTIlength.
 9. The method of claim 8, wherein the ratio is represented asfollows:${10{\log_{10}\left( \frac{{TTIsymbols}_{selected}}{{TTIsymbols}_{predetermined}} \right)}},$wherein TTIsymbols_(selected) is the selected number of TTI symbols, andTTIsymbols_(predetermined) is the predetermined number of TTI symbols.10. The method of claim 9, wherein the ratio is further represented asfollows:${{a\; 10{\log_{10}\left( \frac{{TTIpilotsymbols}_{selected}}{{TTIpilotsymbols}_{predetermined}} \right)}} + {b\; 10{\log_{10}\left( \frac{{TTIcontrolsymbols}_{selected}}{{TTIcontrolsymbols}_{predetermined}} \right)}}};$wherein the selected number of TTI symbols corresponds to a selectednumber of pilot symbols (TTIpilotsymbols_(selected)) and a selectednumber of control symbols (TTIcontrolsymbols_(selected)); wherein thepredetermined number of TTI symbols corresponds to a predeterminednumber of pilot symbols (TTIpilotsymbols_(predetermined)) and apredetermined number of control symbols(TTIcontrolsymbols_(predetermined)); and wherein a and b are constants.11. The method of claim 9, wherein the selected number of TTI symbolscorresponds to a short TTI having a length of less than 14 symbolsand/or the predetermined number of TTI symbols is fourteen.
 12. Themethod of claim 8, wherein the ratio is represented as follows:${10{\log_{10}\left( \frac{{TTIlength}_{selected}}{{TTIlength}_{predetermined}} \right)}},$wherein TTIlength_(selected) is the selected TTI length, andTTIlength_(predetermined) is the predetermined TTI length.
 13. Themethod of claim 12, wherein the selected TTI length corresponds to ashort TTI having a length of less than one millisecond and/or thepredetermined TTI length is one millisecond.
 14. The method of claim 8,wherein the ratio is further represented as follows:${{a\; 10{\log_{10}\left( \frac{{TTIpilotlength}_{selected}}{{TTIpilotlength}_{predetermined}} \right)}} + {b\; 10{\log_{10}\left( \frac{{TTIcontrollength}_{selected}}{{TTIcontrollength}_{predetermined}} \right)}}};$wherein the selected TTI length corresponds to a selected pilot symbolslength (TTIpilotlength_(selected)) and a selected control symbols length(TTIcontrollength_(selected)); wherein the predetermined TTI lengthcorresponds to a predetermined pilot symbols length(TTIpilotlength_(predetermined)) and a predetermined control symbolslength (TTIcontrollength_(predetermined)); and wherein a and b areconstants.
 15. The method of claim 1, wherein the value of the at leastone parameter is based on a ratio of the selected TTI length and apredetermined TTI length.
 16. The method of claim 1, wherein the valueof the at least one parameter is based on a predetermined received powerfor the physical channel having the selected TTI length.
 17. The methodof claim 1, wherein the value of the at least one parameter is based onan adjustment that depends on whether frequency hopping is used for thetransmission on the physical layer having the selected TTI length. 18.The method of claim 1, wherein the physical channel is a control channeland/or an uplink channel.
 19. A wireless device for performing powercontrol of physical channels in a wireless communication system,comprising: processing circuitry; memory containing instructionsexecutable by the processing circuitry whereby the wireless device isoperative to: determine a transmission power for a transmission on thephysical channel according to a power control loop; wherein the loopspecifies the transmission power based on at least one parameter, with avalue of the at least one parameter being dependent on which ofdifferent transmission time interval (TTI) lengths defined as usable onthe physical channel is selected for the transmission on the physicalchannel.
 20. The wireless device of claim 19, wherein the value of theat least one parameter further depends on which of differenttransmission formats defined as usable on the physical channel isselected for the transmission on the physical channel.
 21. The wirelessdevice of claim 19, wherein the value of the at least one parameter isbased on a number of symbols in the transmission on the physical channelhaving the selected III length.
 22. A method for performing powercontrol of physical channels in a wireless communication system, themethod comprising a network node: transmitting, to a wireless device, anindication of a value of at least one parameter which is dependent onwhich of different transmission time interval (TTI) lengths defined asusable on the physical channel is selected for the transmission on thephysical channel; wherein a transmission power for a transmission by thewireless device on the physical channel is according to a power controlloop; and wherein the power control loop specifies the transmissionpower based on the parameter.
 23. A network node for performing powercontrol of physical channels in a wireless communication system, thenetwork node comprising: processing circuitry; memory containinginstructions executable by the processing circuitry whereby the networknode is operative to: transmit, to a wireless device, a value of atleast one parameter which is dependent on which of differenttransmission time interval (TTI) lengths defined as usable on thephysical channel is selected for the transmission on the physicalchannel; wherein a transmission power for a transmission by the wirelessdevice on the physical channel is according to a power control loop; andwherein the power control loop specifies the transmission power based onthe parameter.